Many current pass card (e.g. identification) systems use a magnetic strip on a card to store coded information. While this method can store many bytes of data, it is prone to data corruption if the card is placed in a strong magnetic field. Over time, the magnetic strip loses its ability to store information, making it necessary to replace the card. Other pass card systems use bar-codes to represent coded information. Bar-codes are unique combinations of like white and black areas that represent coded information. Bar-codes cannot be corrupted other than by physical destruction of the card or the bar-code itself. While information coded as a bar-code can be thought of as fairly permanent, not much data can be stored in a given area.
In response to this, I developed, and herewith describe, a novel "Gray Shade Pass Card Reader" as a new kind of pass card that offers the durability of a bar-code system, yet can store much more information in a given area. A complete system is proposed defining this new pass card and the electronics used to retrieve and process the information encoded thereon.
Objectives
A. To define a new technique for storing small amounts of data on a pass card using of gray areas of various shades, each shade to represent a particular information bit.
B. To define the electronic hardware necessary to successfully retrieve the information from such a gray shade pass card and prepare it for processing by a computer.
C. To describe a working system that uses microcontroller technology to process the code from the pass card, to determine if the code is valid and then allow access to a restricted area.
Workers Will Note Below That
1. The format of such pass cards has been defined. Specific gray shades have been selected to represent the numbers 0 through 7. The pass cards also have calibration areas, plus clock marks, plus an area for determining the direction of the card as it is swiped through a read head.
2. The read head is described along with the electronics that convert each gray shade area to digital data.
3. Also proposed is a microcontroller using the Motorola 68010 microprocessor, and including PROM containing a simple monitor program, plus RAM and a serial interface to a terminal.
4. A schematic defining the electronics; and
5. An outline of the code used by the microcontroller to process the information on the pass card.
Thus, it is an object hereof to address (at least some of) the aforementioned problems, and to provide the hereincited advantages and functions. A related object is to provide a gray shade pass card system.
The methods and means discussed herein, will generally be understood as constructed and operating as presently known in the art, except where otherwise specified; with all materials, methods and devices and apparatus herein understood as implemented by known expedients according to present good practice.